Google’s parent company Alphabet told a TED conference in Vancouver that its Project Loon Internet-delivery balloons had successfully delivered speeds of 15Mbps – fast enough for streaming video. It is preparing for carrier tests in Indonesia and elsewhere this year.

Alphabet X head Astro Teller said that the company tried a lot of unsuccessful balloon designs before finally finding one that was up to the job, reports Re/code.

There were shiny balloons and round balloons and balloons that looked like giant pillows. But eventually the company found a design that could be made cheaply and still navigate precisely. That balloon, Teller said, last year travelled around the world 19 times over 187 days last year.

Teller also shared a key part of the company’s approach to Alphabet X projects, along with details of two which the company has abandoned …

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Starting with testing out the hardest part of a project, Teller said, is part of how X decides which projects to kill and which to continue with. The company starts with the hardest pieces of a potential “moonshot,” and only funds those that can survive the toughest tests.

The unit, he said, depends on both wild dreaming and what he called “enthusiastic skepticism.”

One abandoned project was vertical farming, which would have used 1/100th of the land needed for conventional farming.

But although Google grew some lettuce, it never managed to grow staple crops like grain or rice.

Another was using rocket cargo ships for cargo delivery, abandoned as soon as the company did the sums.

The idea itself might have worked, Teller said, but just building the first unit would have cost $200 million. Even for a company with Google’s riches, that proved too much to gamble.

Google is also experimenting with solar-powered drones to deliver high-speed Internet from the air. It’s not known at this point whether the two projects are designed to work in tandem, or have different aims.